chore: add experiment toggle for terraform workspace caching (#20559)

Experiments passed to provisioners to determine behavior. This adds
`--experiments` flag to provisioner daemons. Prior to this, provisioners
had no method to turn on/off experiments.

enterprise/cli/provisionerdaemonstart.go

@@ -23,6 +23,7 @@ import (
 	"github.com/coder/coder/v2/cli/clilog"
 	"github.com/coder/coder/v2/cli/cliui"
 	"github.com/coder/coder/v2/cli/cliutil"
+	"github.com/coder/coder/v2/coderd"
 	"github.com/coder/coder/v2/coderd/database"
 	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/codersdk/drpcsdk"
@@ -48,6 +49,7 @@ func (r *RootCmd) provisionerDaemonStart() *serpent.Command {
 		preSharedKey   string
 		provisionerKey string
 		verbose        bool
+		experiments    []string
 
 		prometheusEnable  bool
 		prometheusAddress string
@@ -186,6 +188,7 @@ func (r *RootCmd) provisionerDaemonStart() *serpent.Command {
 						Listener:      terraformServer,
 						Logger:        logger.Named("terraform"),
 						WorkDirectory: tempDir,
+						Experiments:   coderd.ReadExperiments(logger, experiments),
 					},
 					CachePath: cacheDir,
 				})
@@ -378,6 +381,14 @@ func (r *RootCmd) provisionerDaemonStart() *serpent.Command {
 			Value:       serpent.StringOf(&prometheusAddress),
 			Default:     "127.0.0.1:2112",
 		},
+		{
+			Name:        "Experiments",
+			Description: "Enable one or more experiments. These are not ready for production. Separate multiple experiments with commas, or enter '*' to opt-in to all available experiments.",
+			Flag:        "experiments",
+			Env:         "CODER_EXPERIMENTS",
+			Value:       serpent.StringArrayOf(&experiments),
+			YAML:        "experiments",
+		},
 	}
 	orgContext.AttachOptions(cmd)
 

enterprise/cli/testdata/coder_provisioner_start_--help.golden

@@ -6,6 +6,11 @@ USAGE:
   Run a provisioner daemon
 
 OPTIONS:
+      --experiments string-array, $CODER_EXPERIMENTS
+          Enable one or more experiments. These are not ready for production.
+          Separate multiple experiments with commas, or enter '*' to opt-in to
+          all available experiments.
+
   -O, --org string, $CODER_ORGANIZATION
           Select which organization (uuid or name) to use.